Objective: To provide and facilitate morphological evaluation to DERC investigators. The goal has been to have sophisticated morphological techniques readily available to all investigators at this Center by providing electron microscopic services and a confocal microscope facility. In addition, the Core has been a resource for protocols, analysis and interpretation, and equipment for paraffin and cryostat sectioning. With the increased use of transgenic and null mice, the need for paraffin embedding/sectioning and cryostat sectioning has become greater. Understanding these mice has mandated histological assessment of many tissues initially and then specific tissues in greater detail. In the past most investigators have sent their samples out to other institutions for these services. In answer to this demand, we have added a Histology component to this Core by expanding the personnel, equipment and space for the Core.